This invention relates to laundry prespotting compositions. More particularly this invention relates to aqueous laundry prespotting compositions having excellent stain removal properties.
Current commercially available prespotting compositions fall into two categories, those based primarily upon water and those based primarily upon solvents. The aqueous based prespotting compositions are primarily non-aerosol formulations intended for use in trigger spray bottles or squeeze bottles. These aqueous based prespotting compositions have good stain removal characteristics against the so-called water-borne stains. These stains include grape juice, mustard, grass, chocolate, clay and similar stains.
The solvent based composition formulations typically have been packaged in aerosol form. These solvent-based compositions typically are more effective in removing oil-borne stains, such as cooking oil, fat, spaghetti sauce, sebum, grease, motor oil and the like. It is possible to formulate solvent-based prespotting compositions with reasonable water-borne stain remover. However it is desirable to use a composition which has good removal for both water-borne and oil-borne stains.
There have been attempts to replace the solvent with water in prespotter compositions for both aerosol and non-aerosol formulation types. One approach is described in U.S. Pat. No. 4,438,009, issued Mar. 20, 1984. The compositions described in this patent are emulsions containing a salt, a nonionic surfactant, from 5 to 60% by weight of a solvent, and water. These compositions are described as having good stain removal properties but these compositions require that some solvent be present for the enhanced stain removal.
Another approach is set forth in U.S. Pat. No. 4,079,078, issued Mar. 14, 1978. A typical formulation having certain ingredients corresponding to the teachings of that patent is tested in Example I herein as a comparative formulation. Such compositions require a nonionic surfactant, an anionic surfactant, an alkanolamine, a base, water, a fatty acid corrosion inhibitor, as oleic acid, and optionally, an electrolyte salt to reduce gel formation, such as sodium citrate, and a color stabilizing agent, as citric acid in amounts of up to 1%.
Most commercially available liquid prespotting formulations are totally aqueous. These aqueous formulations exhibit good stain removal for the water-borne stains but are inferior to solvent based prespotters for oil removal.
Most aerosol prespotting formulations and a few liquid formulations are totally non-aqueous. These formulations have excellent oil-borne stain removal but are less effective against water-borne stains. Further, these solvent products often contribute to soil redeposition.